1. Field of the Invention
The present invention relates to tilt-up construction. In particular, the present invention relates to brackets used to support form sides. And in more particularity, the present invention relates to non-destructive form brackets which eliminate the use of concrete nails as a means of attaching form brackets to the floor slab or foundation.
2. Background of the Invention
Tilt-up construction is one of the fastest growing industries in the United States. At least 10,000 buildings enclosing more than 650 million square feet are constructed annually. This is due, in part, to the economics of tilt-up, which combine reasonable cost with low maintenance, durability, speed of construction, and minimal capital investment. The tilt-up process requires few forms and makes efficient use of modern mechanical equipment. Ready mixed concrete for tilt-up is locally available and special labor skills are not required. Panels are formed and cast on the jobsite, and can be quickly tilted, lifted, set in place, and braced with the aid of high capacity mobile cranes.
Simplicity is the key to tilt-up concrete construction. Panels are cast as near to their final position as possible. The most convenient casting base is most often the concrete floor slab of the building. Wood or steel edge forms are prepared and positioned on the casting base. Reinforcing steel, vapor seal, insulation, door and window frames, electric conduit, and outlet boxes are then positioned. Wall panels are cast on the horizontal base, cured, tilted into a vertical position and moved into place with a mobile crane.
The standard practice in laying out panels is to snap a chalk line on the floor slab. These lines indicate panel perimeters and the forms are placed against them. Wood 2×s are the most common material used for side forms. Often the panel depth is designed to fit the depth of standard dimension lumber, so 5½″ (a.k.a. “6×s”) and 7¼″ (a.k.a. “8×s”) structural panels are common. Typically, the form sides are supported and secured to the foundation by a wood or steel angle support. Any common concrete anchor can be used to attach forms to the foundation. For instance, it is most common to pneumatically drive concrete nails using a nail gun into the foundation.
Although tilt-up construction does have many advantages, there are some aspects of tilt-up construction which can still use some refinement. Most noticeable is the damage that is inflicted to the top of the foundation from the nails or concrete anchors that are driven into the foundation or floor slab. Typically, an area where the nail was embedded must be patched. Not only are the patches unsightly, but the damage inflicted into the concrete wall can be harmful to the structural integrity of the concrete structure. Also, many times a water membrane barrier is laid down in the foundation and the nails penetrate the membrane.
It would be advantageous to provide a bracketing system which is non-destructive to the foundation or floor slab of which tilt-up panels are formed. Ideally, the bracketing system would be simple to use and inexpensive. It would further be advantageous to provide an attachment plate or piece which could be retrofitted or designed to be used in conjunction with existing angles brackets, such SIMSPON “Strong Tie” brackets.